Discharging exhaust products from a torpedo



Aug. 7, 1962 G. CALEHUFF DISCHARGING EXHAUST PRODUCTS FROM A TORPEDOFiled May 17, 1957 G/RARD L. CALEHUFF IN V EN TOR.

BY JzM/LQ 241% A T TORNEYS 3,b48,l37 Patented Aug. 7, 1962 3,048,137DISCGING EUST RR'DDUCTS FRQM A TGRPEDO This invention relates generallyto torpedoes and it has particular reference to certain structuralfeatures for discharging exhaust products from a propeller driventorpedo.

For torpedoes provided with a turbine propulsion motor it has been theconventional practice to exhaust the turbine gases through the center ofthe propeller shaft, thereby requiring complicated and expensivemechanism for the discharging of the exhaust products in this manner.Previous attempts to place exhaust ports in the torpedo tail coneforwardly of the propeller have resulted in instability of the torpedoand the provision of an expansion chamber or the like rearwardly of thetorpedo propeller places serious limitations on the form and operationof the expansion chamber and often prohibits conventional handlingand/or firing of the torpedo, not to mention the fact that it stillrequires the complicated and expensive mechanism referred to hereinabovenecessary to exhaust the turbine exhaust products through the propellershaft or shafts.

It is an object of the invention to provide a new and novel means forexhausting turbine gases in a torpedo.

Another object of the invention is the provision of exhaust meansforward of the propeller whereby the ex- Must products of the turbinepropulsion motor may be circumferentially exhausted in small bubbles atsuch a rate as to not create an undue back pressure on the turbine andat such a velocity that the bubbles'as they progress upwardly willsubstantially remain within the boundary layer which surrounds thetorpedo when in motion thereby not affecting the efficiency of thepropeller.

A further object of the invention is the provision of a new and novelmeans for exhausting turbine exhaust gases from a torpedo whereby thenecessity of complicated and expensive mechanisms required by theconventional method of exhausting such gases through one or more hollowpropeller shafts may be eliminated.

These and other objects and features of the invention, together withtheir incident advantages will be more readily understood andappreciated from the following detailed description of a preferredembodiment thereof selected for purposes of illustration and shown inthe accompanying drawing, in which:

FIGURE 1 is a longitudinal sectional view of the tail cone of a torpedoconstructed in accordance with the principles of the invention;

FIGURE 2 is a cross sectional view taken on line 2-2 of FIGURE 1.

Torpedoes of conventional design with which the invention finds itsgreatest utility are commonly referred to as steam torpedoes and aregenerally divided into a plurality of longitudinal sectional componentswhich are joined by water tight clamping rings. These sections generallycomprise a warhead which is the forward extremity, an air flask disposedrearwardly of the warhead, an afterbody section which may house certaincontrol components and the like and a tail cone which carries theturbine propulsion motor and associated shafting, the propeller, and thehorizontal and vertical control surfaces and rudders.

With reference now to FIGURE 1, there is shown a tail cone 10 asreferred to hereinabove having a propeller 11 mounted in theconventional manner at its rearmost extremity, a propeller shaft 12disposed and supported within the tail cone ill in the conventionalmanner for rotatably driving the propeller 11 and a conventional torpedoturbine propulsion motor 13 connected in driving relationship with thepropeller shaft 12 to secure the desired rotational speed of thepropeller 11. An outer covering 14 of metal or the like and a bulkhead15 provide means for rigidly supporting the propulsion motor in theconventional manner. Attached to the rear periphery 16 of the metal skin14 as by continuous welds 17 to form Water tight joints is a wall orbulkhead of considerable rigidity and strength forming a forward wall 18of a plenum or expansion chamber 19, said wall 18 being provided with anaxial passage 21 of such size as to freely receive the propeller shaft12. A plurality of radially disposed ribs 22 are welded to the metalskin 14 and the Wall 13 to provide additional stiffness to the wall andto reduce any flexing thereof. A turbine exhaust conduit 23 is connectedbetween the turbine exhaust outlet 24 and a passage 25 in the forwardwall 18 whereby the turbine exhaust products may be directed into theplenum or expansion chamber 19 disposed intermediate the turbinepropulsion motor 13 and the propeller 11.

The rear periphery 16 of the metal skin 14 forming the outer surface ofthe forward portion of the tail cone 10 is provided with an enlarged andthickened portion 26 to which the expansion chamber forward wall 18 isattached as by continuous welds 17 at surface 27 and which is furtheradapted to receive the forward periphery 28 of the expansion chamberouter wall 29 as at groove 31 formed by projection 32. The rear portionof the tail cone is provided with an outer covering 33 of sheet metal orthe like attached and formed in the conventional manner and provided atits forward periphery 34 with an enlarged and thickened portion 35substantially identical to the enlarged portion 26 referred tohereinabove and also provided with a groove 36 formed by projections 37to receive the rear periphery 38 of the expansion chamber outer wall 29.A rear wall or bulkhead forming the rear Wall 39 of the expansionchamber 19 is attached to surface 41 as by continuous welds 42 and isprovided with an axial passage 43 having a diameter substantially equalto the axial passage 21 in the expansion chamber forward Wall 1%. Radialribs 44 are attached to the outer covering 33 and the rear wall 39 as bywelding to strengthen the rear wall and to prevent movement or vibrationthereof, Disposed between the expansion chamber forward wall 18 and rearwall 39 is an annular inner wall 45 having an inside diameter preferablygreater than the diameter of the axial passages 21-43 and rigidlyattached to the forward and rearward expansion chamber walls 18-39 atits forward and rearward periphery 46-47 as by welding or the like. Theannular inner wall 45 is of such thickness and diameter as to provide asubstantially non-flexible connection between the expansion chamberforward wall 18 and rearward wall 39 and provided with an insidediameter such that electrical conduits and/or rudder operatingmechanisms or the like may be placed in operational communication withthe rear portion of the tail cone without interfering with or beingdamaged by rotation of the propeller shaft 12. If desired walls 18-39and their respective axial passages 21-43 may be adapted to receivebearings in which the propulsion shaft may be journalled.

A comically shaped expansion chamber outer wall 29 surrounding anddisposed away from the annular inner wall 45 and forming a smoothcontinuation of the tail cone outer surface is securely attached at itsforward and rearward periphery 28-37 to the projections 33-37 as byscrews 48 or the like and provide the means for exhausting the turbineexhaust products as and for the purposes hereinafter described. Theexpansion chamber outer wall 29 preferably extends circumferentiallyaround serene? the center portion of the tail cone and is comprised of aporous or foraminous material such as for example compacted fibre glass,sintered metallic material or the like having a large number of foramina39 per unit area. Since the expansion chamber outer wall 29.is subjectedto only minor stresses in actual service it need not be structurallystrong thereby allowing a high concentration of foramina which resultsin a practically operative exhaust system forwardly of the propeller. Asused herein, a foramina is defined to be a more or less transverselydisposed passage in the expansion chamber outer wall 29 of such diameteras to allow the expulsion of exhaust gases there through in a smallcolumn or a series of minute bubbles. For most satisfactory operationthe expansion chamber outer wall 29 should contain a high concentrationof foramina 30 per unit area, there being a substantially uniformdistribution thereof over the entire outer wall.

Horizontal fins 49 and vertical fins 51 having respectively depth andsteering rudders 52--53, there being two fins in each horizontal andvertical group and the pairs of each group being arranged in 180relation, are welded longitudinally of the tail cone It) at theirforward and rearward portions 54-55, the inner surface 56 of the middleportion being preferably disposed away from and above the expansionchamber outer wall 29 to allow the exhausting of the turbine exhaustproducts through the portion of the outer wall that would normally becovered by the fins. However, it is to be noted that if sufficient areais made available in the manner hereinafter described the middleinnerportion of the fins may be adjacent to and in contact with theexpansion chamber outer wall. To secure structural rigidity the fins maybe fabricated of a plurality of ribs shaped to the cross sectionalconfiguration of the fins and over which a two piece shaped sheet metalcovering butt jointed and welded along the fin edge, is secured. Thefins may extend over roughly three-quarters of the length of the tailcone beginning at the forward extremity thereof, and by reason of theirrigid construction and the secure attachment to the tail cone at theirforward and rear portions function as reinforcing elements incooperation with the expansion chamber forward wall 18, annular innerwall 45 and rear wall 39 to impart both longitudinal and lateralstiffness to the tail cone thereby resulting in a structure allowing theuse of a structurally weak expansion chamber outer wall 29.

The efficiency of the operation of the expansion or plenum chamber 19basically depends upon the ratio of the rate of expulsion of exhaustgases through the expansion chamber outer wall 29 to the rate at whichthe exhaust gases are exhausted into the expansion chamber 19; and theconcentration and distribution of the foramina in the expansion chamberouter wall 29. The requisite concentration and distribution of foraminaper unit area of the outer wall is controlled by the selection of asuitable material such as for example porous fibreglass or the like andthe ratio referred to hereinabove may be determined by the longitudinallocation of the expansion chamber 19 in the tail cone 10 and thelongitudinal distance between the forward and rearward walls 18-39 ofthe expansion chamber, the latter obviously resulting in a determinationof the total area of the expansion chamber outer wall 29.

The determination indicated immediately hereinabove must be such thatthe exhaust gases from the turbine will be exhausted through theexpansion chamber outer wall 29 in minute bubbles evenly andcircumferentially and a relatively low velocity, the velocity being suchthat the thickness in a radial direction of the rearwardly movingbubbles will be of an order not greater than the boundary layer andpreferrably not greater than the laminar sublayer of water thatsurrounds the torpedo when in actual service. If the thickness of therearwardly moving exhaust gases is of an order less than the boundarylayer surrounding the tail cone the efiiciency of the propeller will besubstantially unaffected since the bubbles will flow over and past thepropeller hub 57 and a portion of the root section 58 of the propellerblades that are not effective in contributing to the thrust developed bythe propeller.

As may now be obvious, in view of the foregoing description, the exhaustproducts of the turbine are directed into the expansion chamber 19 viathe conduit 23 connecting the exhaust outlet 24 of the turbine 13 andthe forward wall 18 of the expansion chamber. When the pressure in theexpansion chamber 19 becomes sutliciently high, but below that whichwould amount to an undesirable back pressure on the turbine, the exhaustgases will be uniformly forced through the outer wall in the mannerdescribed and exhausted at a velocity insufiicient to cause them to beprojected past the boundary layer and will travel rearwardly remainingsubstantially within the boundary layer thereby passing the rudders 5253and propeller 11 without creating any substantially undesirable effects.

While the present invention has been described in its preferredembodiment it is realized that modifications may be made, and it isdesired that it be understood that no limitations upon the invention areintended other than may be imposed by the scope of the appended claims.

Having now disclosed my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In exhaust means for a torpedo having a turbine propulsion motor anda propulsion shaft mounting a propeller for propelling the torpedo thecombination comprising: an expansion chamber disposed between thepropeller and the turbine, said expansion chamber comprising a forwardwall, a rearward wall and a longitudinally disposed annular inner wallintegral with and supported by said forward and rearward walls andaccessible at both ends to freely receive said propulsion shaft; conduitmeans for directing the exhaust gases of said turbine into saidexpansion chamber; and a porous expansion chamber outer wall disposedaway from and enclosing said annular inner wall whereby the gasesexhausted into said expansion chamber will be exhausted through saidouter wall, said outer wall having an area and porosity whereby saidgases will be substantially circumferentially exhausted through saidwall at a low velocity and at a rate sufiicient to prevent a substantialback pressure on said turbine.

2. In exhaust means for a torpedo having a turbine propulsion motor anda propulsion shaft mounting a propeller for propelling the torpedo thecombination comprising: an expansion chamber disposed between saidpropeller and said turbine, said expansion chamber comprising a forwardwall having a first axial opening and integral at its outer peripherywith said torpedo, a rear wall having a second axial opening concentricwith said first opening and integral at its outer periphery with saidtorpedo, and a longitudinally disposed annular inner wall disposedbetween said forward wall and said rear wall and integral therewith atsaid first and second openings; first support means forward of saidforward Wall and integral therewith; second support means rearward ofsaid rear wall and integral therewith, said forward wall, rear wall andannular inner wall being disposed and adapted to provide a rigid unit,said first and second openings and said annular inner wall being furtheradapted to rotatably receive said propulsion shaft; conduit means fordirecting the exhaust gases of said turbine into said expansion chamber;and a porous expansion chamber outer wall disposed away from andenclosing said annular inner wall whereby the gases exhausted into saidexpansion chamber will be exhausted through said outer wall, said outerwall having an area and porosity whereby said gases will besubstantially circumferentially exhausted through said wall at a lowvelocity and at a rate suflicient to prevent a substantial back pressureon said turbine.

3. In exhaust means for a torpedo having a gas driven turbine propulsionmotor and a propulsion shaft mounting a propeller for propelling thetorpedo the combination comprising: a forward wall having a first axialopening and integral at its outer periphery with said torpedo; a rearwall having a second axial opening concentric with said first openingand integral at its outer periphery with said torpedo; a longitudinallydisposed annular inner wall disposed between said forward wall and saidrear wall and integral therewith at said first and second openings;first support means forward of said forward wall and integral therewith;second support means rearward of said rear wall and integral therewith,said forward wall, rear wall and annular inner wall being disposed andadapted to provide a rigid unit, intermediate said turbine and saidpropeller, said first and second openings and said annular inner wallbeing further adapted and disposed to rotatably receive said propulsionshaft; conduit means conmeeting said turbine and said forward Wallwhereby the exhaust gases from said turbine may be exhausted rearwardlythrough said forward wall; and a porous outer wall carried by saidtorpedo and disposed away from and enclosing said annular inner wallwhereby the turbine exhaust gases will be exhausted from the torpedothrough said outer wall, said outer Wall having an area and highconcentration of foramina per unit area whereby said gases will besubstantially circumferentially exhausted through said wall at a lowvelocity and at a rate sufficient to prevent a substantial back pressureon said turbine.

4. The combination as described in claim 3 wherein said outer wall iscomposed of a foraminous fiberglass composition.

5. The combination as described in claim 4 wherein said foraminous outerwall contains foramina of such size, distribution and number whereby theexhaust gases are evenly and circumferentially exhausted in minutebubbles at a velocity such that they remain substantially within thefluid boundary layer surrounding said outer wall when the torpedo is inmotion.

6. The combination as described in claim 5 additionally including aplurality of rigid radially extending and longitudinally disposedstabilizer fins having a front portion, a middle portion and a rearportion, said front portion being fixedly attached to said torpedoforwardly of said forward wall, said middle portion being disposedadjacent said outer wall and said end portion being fixedly attached tosaid torpedo rearwardly of said rear wall whereby movement of said rearwall with respect to said forward wall is substantially prevented.

References Cited in the file of this patent UNITED STATES PATENTS1,541,689 Davis June 9, 1925

